Process for the control of boll weevil and boll worm with tde

ABSTRACT

A PROCESS OF COMBATTING BOLL WORM IN COTTON BY SPRAYING THE COTTON WITH A 1,1-DICHLORO-2,2-BIS PARACHLOROPHENYL ETHANE, COMMONLY KNOWN AS TDE, DISSOLVED IN CYCLOHEXANONE.

United States Patent US. Cl. 424-35 3 Claims ABSTRACT OF THE DISCLOSUREA process of combatting boll worm in cotton by spraying the cotton witha 1,1-dichloro-2,2-bis parachlorophenyl ethane, commonly known as TDE,dissolved in cyclohexanone.

This application is a division of application Ser. No. 647,616, filedJune 21, 1967 now US. Pat. No. 3,480,710.

BACKGROUND OF THE INVENTION This invention relates to a process ofcontrolling insect pests infesting cotton and, more particularly, to aprocess of simultaneously controlling the two major cotton pests, namelycotton boll Weevil, Anthonomus grandis, and the cotton boll worm,Heliothis zea by the spray of applications of TDE and a mixture of TDEand malathion.

Cotton is a major crop in many areas of the country, and the control ofinsects destructive or injurious to cotton plants is essential if thegrowing of cotton is to survive and be profitable.

For many years, a variety of insecticides have been applied to thecotton plant to control one or another of the major cotton pests.Usually such insecticides have been applied as specially formulatedsolid dusts or aqueous emulsion sprays. Such dusts or sprays frequentlycontained a mixture of toxicants designed to control several cottonpests when such toxicants were compatible.

In recent years aerial applications of dusts and sprays have becomecommon, said aerial spray applications being made at rates from 1 to 3gallons total volume per acre of dilute aqueous emulsions to apply atotal of about 6-8 pounds of active toxicant per acre.

Aerial spraying, as by atomized application from airplanes, wasexpensive in requiring application of large volumes of diluent, usuallywater, to apply small amounts of toxicant.

The recent development of a new type of spray nozzle, equipped with flatspray tips, and called the Mini-Spin nozzle, (described in FarmTechnology for April 1965, pages 9 and 10), has permitted the undilutedspray application of low volumes of certain low viscosity liquidinsecticides whereby application rates are reduced as much as 90% ormore.

In the Mini-Spin nozzle, as in others of a similar type, the liquidtoxicant is delivered to a circular fine mesh screen cage about twoinches in diameter which is propeller driven. The spray droplets arethrown by centrifugal force through the screen and are atomized indroplets of between about 50 microns and about 100 microns in size.These sprays of droplets are preferably applied from a height of notmore than about 20 feet above the cotton plants, preferably betweenabout feet and about feet. Application may be made either by airplane orby ground rigs. For adequate coverage, between about 50 droplets andabout 500 droplets of the above size range should be applied per inch.

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Particularly adapted for application in this manner, is the pesticideknown as rnalathion, which is chemically, 0,0-dimethylphosphorodithioate of diethyl mercaptosuccinate.

This material is a very low viscosity liquid, of the order of about 45centipoises at 20 C., and has found wide use by means of the newtechnique in controlling boll weevil in large cotton plantings. However,it is ineffective in controlling boll worm infestations at lowconcentrations. Thus, if complete protection of the cotton crop is to beeffected, a second spraying of a boll worm toxicant must be made by theold, high volume spray application.

Application of the major known boll worm toxicants by the new method isnot feasible since the best of such compounds are either solids like TDE(1,1-dichloro-2,2- bis(parachl0rophenyl) ethane), DDT,(dichlorodiphenyltrichloroethane), and Sevin (l-naphthyl-N-methylcarbamate) or viscous liquids such as Strabane (polychlorinatedterpenes), and Toxaphene (chlorinated camphene). All of the abovecompounds have such low solubilities in common solvens that they cannotfeasibly be used in the new low volume spray applications. Moreover,solvents such as acetone, methyl ethyl ketone, benzene, toluene anddioxane all have flash points below about 12 C. and so would pose anexplosive hazard if compositions containing them were sprayed into theatmosphere. Further, solvents such as kerosene and the lower alkanes aswell as xylene have low solubilizing power for the abovenamedinsecticides, and all except xylol and cyclohexanone have vaporpressures so high as to be unsuitable, since evaporation on atomizationwould so reduce the size of the droplets that excessive drift andunsatisfactory coverage of the cotton plant would result.

It is an object of this invention to produce homogeneous liquidsolutions of TDE.

It is an additional object of this invention to produce homogeneousliquid solutions of TDE and malathion.

It is a further object of this invention to produce homogeneous liquidsolutions of TDE and malathion suitable for low volume aerial spraying.

SUMMARY OF THE INVENTION In accordance with the present invention asolution of the insecticide TDE in cyclohexanone or xylol or in amixture of cyclohexanone and xyol is formed. The solution may then bemixed with malathion to form a homogeneous solution. In this manner thefollowing solutions of the present invention may be formed:

(a) 1-6 pounds of TDE per gallon of cyclohexanone;

(b) 4/ 1 to 3/ 6 pounds of TDE/malathion per gallon, (US) of a mixtureof xylol and cyclohexanone;

(c) 3/ 1 to 2/4 pounds of TDE/malathion per gallon of xylol; and

(d) 3/ 1.5 to 4/4 pounds of TDE/malathion per gallon of cycylohexanone.

This invention also includes the aerial or mechanical spraying, of theabove solutions on cotton crops so as to combat boll weevil and bollworm by spraying 0.2-6.0 pounds of the toxicants TDE or TDE andmalathion per acre of cotton.

It has been discovered that TDE (1,1-dichloro-2,2-bis (parachlorophenyl)ethane), an effective solid boll worm toxicant, can be dissolved incyclohexane or xylol and the resulting solution has fluidity and vaporpressure characteristics adapted for low volume aerial sprayapplication.

Generally 1-6 and preferably 3-6 pounds of TDE per (US.) gallon ofsolvent, xylol or cyclohexanone, may be used to make up a homogeneoussolution having the re- 4 The properties of a few of the above compoundswere evaluated and are listed in Table II in comparison with theproperties of technical grade, 95% malathion.

TABLE II Surface Specific Brookficld tension, gravity, dyncs/ CompoundsConcentration 20 C. Lbs/gal. 20 0. 0. cm.

TDE/malathion 4/4 lbs. per gallon of cyclohexanone 1.2221 10.19 38 9438.2 DE 6 lbs. per gallon of 15% cyclohexanone and 85% 1.1774 9. 80 3153 39. 0 Malathion 1. 2239 10.21 45 120 38.1

quired fluidity and vapor pressure characteristics. Outside of theseranges of concentrations either the solution does not have the requiredfluidity and vapor pressure or the concentration of the TDE is not highenough so that the toxicant is eflective against the boll worm.

Furthermore, a homogeneous, liquid blend of the boll weevil toxicant,malathion, and TDE can be prepared having fluidity and vapor pressurecharacteristics adapted for low volume aerial spray application bymixing generally 3/ 1.5 pounds of TDE and malathion to 4/4 pounds of TDEand malathion per gallon of cyclohexanone solvent. The preferableconcentration is 3/3-4/4 pounds of TDE and malathion per gallon ofcyclohexanone.

Another homogeneous blend having the desirable properties may be formedby dissolving generally 3/1 pounds of TDE/malathion to 2/ 4 pounds ofTDE/malathion per gallon of xylol. The preferable concentrations are 1/4 to 2/4 pounds of TDE/malathion per gallon of xylol.

An additional homogeneous blend having the desirable properties may beformed by generally mixing 4/1 pounds of TDE/malathion to 3/6 pounds ofTDE/malathion per gallon of a mixture of cyclohexanone and xylol.Generally the weight percent of cyclohexanone in the cyclohexanone andxylol solution mixture may vary from 5-50% and preferably from 8-25 Thepreferable concentration range of TDE/malathion is 4/2 to 4/4 pounds pergallon of solvent mixture (cyclohexanone and xylol).

The TDE, malathion solutions are formed by dissolving the requiredamount of TDE in the solvent (cyclohexanone, xylol or a mixture ofcyclohexanone and xylol) and then adding to this the required amount ofmalathion. Malathion at 95% purity, technical grade was foundsatisfactory for these purposes.

While the percentages of the several components can be varied somewhat,substantial deviation from the proportions indicated produces a lesssatisfactory composition. Adding larger proportions of cyclohexanonewould not only dilute the high toxicant ratio but would also tend toreduce the droplet size produced in the atomization process, thusincreasing drift and reducing coverage. Smaller proportions ofcyclohexanone would fail to dissolve sufficient TDE and would reduce thecompatibility of the malathion with the TDE solution.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Using the above method thefollowing solutions were 4 Ic)ycl0hexanone and 85% xylol.

Cyclohexanone.

12.0% cyclohexanone and 88% xylol.

50.0% cyclohexanone and 50% xylol.

10.0% cyclohexanone and 00% xylol.

Low volume applications of the above TDE and malathion solution tocotton crops is possible with the new type of spray nozzles such as theMini-Spin nozzle. When the solutions of the present invention aresprayed over cotton fields in droplets of average diameter between about50 microns and about 100 microns at the rate of generally 0.2-6.0 poundsper acre and preferably 0.5-1.5 pounds of toxicant per acre adequatecontrol of both boll weevil and boll worm is obtained in a single sprayapplication.

The tests below illustrates the aerial application of the solution of4/4 pounds of TDE/malathion per gallon of cyclohexanone solvent to acotton field for the control of boll Weevil and boll worm in comparisonto the other toxicants used for the same purpose. The tests are intendedto be illustrative and exemplary in character, only, and are not to beconsidered as limiting the invention in any way.

TEST I Twelve, 12-acre plots 320 feet wide and approximately 1600 feetlong were utilized to compare three low-volume aerial spray treatmentswith a standard emulsion spray treatment for effectiveness incontrolling a boll worm, H eliothis zea Boddie, infestation in a fieldof cotton. Plots were arranged in randomized blocks with threereplications of each of the four treatments. Two additional unreplicatedlow-volume treatment plots of 18 and 24 acres each were set up in thesame field and a third was situated on a 24-acre plot in an adjacentfield. Low-volume materials were applied at rates from 16 to 42 fluidounces per acre with Mini-Spin nozzles. The airplane was flown ataltitudes of 10 to 50 feet above the cotton to provide swath widths offeet. The standard emulsion spray was applied at the rate of 2 gallonsper acre just above the cotton, covering 40-feet swaths.

ToXaphene-DDT-methyl parathion and Strobane-DDT- malathion, bothformulated with 6.0, 3.0 and 1.5 pounds of the three active ingredientsper gallon and applied at the rate of 42 fluid ounces per acre, wereequivalent in dosage to the standard emulsion spray which was onehalfgallon of toxaphene-DDT-methyl parathion (4-2-1) applied in water at therate of 2 gallons per acre (2 pounds toxaphene, 1 pound DDT and .5 poundmethyl parathion per acre). The other replicated low-volume treatmentwas percent malathion applied at the rate of 24 fluid ounces per acre,approximately 1.9 pounds active ingredient per acre. The 24-acreunreplicated plot in the same field was treated with a low-volumemixture containing 4 pounds of malathion and 4 pounds of TDE per gallonof cyclohexanone at the rate of 32 fluid ounces per acre while the 18acre plot was treated with 16 ounces per acre of a low-volumeformulation of Azodrin containing 4.8 pounds active ingredient pergallon. This gave a dosage rate of 1.0-1.0 pounds of actual toxicant peracre for malathion-TDE and .6 pounds per acre for Azodrin. The 24-acreplot in the adjacent field which had a difierent cultivation andinsecticide-treatment history received 32 fluid ounces per acre of a 4pounds per gallon emulsifiable methyl parathion formulation Withoutwater for the first 2 applications and 24 fluid ounces of 80 percentmethyl parathion (8 pounds per gallon) thereafter. This raised thedosage from 1.0 to 1.5 pounds per acre.

The results of the test are listed in Table :III. All treatapproximately15 feet and the last 8 were applied in ments except low-volume methylparathion resulted in 37.5 foot swath widths from a height ofapproximately adequate control of a serious boll worm infestation. 3feet. All applications of toxapehne plus DDT plus Toxaphene-DDT-methylparathion, and Strobane-DDT- methyl parathion were applied in 37.5 footswath widths malathion in low-volume applications did not differ sigfroma height of approximately 3 feet. Results are listed nificantly from theequivalent dosage of conventional 5 inTable IV.

TABLE IV.-EFFECTIVENESS OF "MALATHION/TDE/CYCLOHEXANONE SPRAY AGAINSTBOLL WEEVILS AND BOLL WORMS IN FIELD COMPARED WITH STANDARD AQUEOUSEMULSION SPRAY Toxaphene, DDT Malathion methyl parathion Control TDE inin aqueous no treatment cyclohexanone emulsion Pounds Toxicant per Acre1+1-2 2. 4+1. 2+0. 6-4. 2

Boll weevil infestation percent punctured squares:

(a) Before treatment 1.3 0 0 (b) After treatment 23. 8 5. 8 4.0 Bollworm-eggs per 100 terminals:

(a) Before treatment 1. l 3.7 3. 2 (b) After treatment 7. 3 12. 5 13. 2Boll worm larvae per 100 terminals:

(a) Before treatment 20.0 21.3 23. 7 (b) After treatment 11. 9 9. 6 4. 0Boll worm square injury, percent:

(a) Before treatment 30.4 25.2 24. 3 (b) After treatment ll. 3 7. 3 4.4Boll wonriboll injury, percent:

(a) Before treatment 34.9 31.2 34.4 (b) After treatment 9. 6 6. 1 3. 8Yield in pounds of seed cotton per acre 530 1, 603 1, 631 Gain overcontrol 1,073 1, 101

water emulsion spray in control of this boll worm in- It can be seenfrom Table IV that the insecticides gave festation. Also, malathion at24 fluid ounces per acre did about equally good control of a heavy bollworm innot differ significantly from the standard. Themalathionfestation. Both reduced the boll worm and square in- TDE andAzodrin treatments in the same field seemed jury significantly belowthat of the untreated check. to be comparable in effectiveness to thereplicated treat- A boll weevil infestation developed in the untreatedments. Boll damage by boll worm was definitely greater check butremained at very low levels in the treated in the portion of theadjacent field treated with low-volume plots. There were significantlyfewer punctured squares applications of methyl parathion. Increasing thedosage in each treatment than in the check. Each treatment of methylparathion from 1.0 to 1.5 pounds per acre produced a significantincrease in yield over the check did not improve control. with nodifference between treatments.

TABLE IIL-MEAN PEROENTAGES OF COTTON SQUARES AND BOLLS INJURED BY BOLLWORMS DURING TREATMENT WITH VARIOUS LOW-VOLUME AERIAL SPRAYS Percentinjured squares and bolls Days after treatment Small Small Small LargeSmall Large Treatment and dosage (pounds per acre) Squares Squares bollsSquares bolls bolls boils bolls bolls Randomized block testToxaphene-DDT-M. Parathion (21.5) (Conventional Standard) 2. 7 2 72.3 1. 5 0.7 2. 3 0.8 0.0 0. 7 Toxaphene-DDT-M. Parathion (21.5) 1 2.3 48 3.8 4.0 3. 5 1. 0 1.3 0.7 2. o Strobane-DDT Malathion (2-1-.5) L 2. 02 5 2. 0 3. 8 3. 2 4. 3 2. 0 1. l 0. 3 Malathion (1.9) 2 2. 7 3 8 3. 82. 5 5. 0 2. 0 l. 3 1. 7 1, 3

Unreplicated trials (Same field) Malathion-TDE (1-1) 3 7. 0 2. 5 2. 5 1.5 1. 0 2. 5 4. 5 2. 0 3. 0 Azodrin (.6) 4 10. 5 6. 0 4. 0 2. 5 2. 5 3. 54. 0 0. 0

Unreplicated trials (Adjacent field) Methyl Parathion (1.0 to 1.5) 5 5.0 5. 0 17. 5 4. 5 11. 5 10. 5 14. 5 9. 0 11. 0

1 42 fluid ounces of a formulation containing 6.0, 3.0, and 1.5 pounds 332 fluid ounces of a formulation containing 4 pounds per gallon of pergallon of the respective active ingredients. each active ingredient.

2 24 fluid ounces of a 95 percent product. 4 l6 fluid ounces of a 4.8pound per gallon glycol formulation.

5 32 fiuid ounces of a 4.0 pound emulsifiable concentrate ior first twoapplications, 24 fluid ounces of an 8 pound per gallon materialthereafter.

TEST II It is apparent that the malathion, TDE, cyclohexanonecomposition produces control of both boll worm and boll Technlcalmalathlon at Pound P TDE at weevil virtually equal to the standardaqueous emulsion pou d p r gallon of cyclohexanone applied as an ultraeven when used at less than half the total dosage oflow-volume spray andtoxaphene at 2.4 pounds plus DDT at 1.2 pounds plus methyl parathion at0.6 pound to ventlon 1n any way but are merely descrlptlve of the wormand boll weevil. Plots were 13 to 22 acres 1n size with 15 sub-plots ineach treatment. Applications of inmethod' All fall Wlthm the SPlYltSeetieides were made with aerial equipment The total 0 of the presentinvention are clalmed as part of the present toxicant per acre.

The illustrations of the method that constitutes the volume of malathionplus TDE applied was 32 ounces invention: per acre and the total volumeof toxaphene plus DDT We clam: plus methyl parathion water mixture was 2gallons per In the art of undlhlted p y appllcatlon of 10W acre. Thefirst 3 applications of malathion plus TDE, volumes of cotton boll wormand boll weevil toxicants were applied in foot swath widths from aheight of 75 by means of aerial or ground-rig sprays of droplets of 8between about 50 microns and about 100 microns in References Cited i ppfrom a height of not more than about 2 Burgess J. Econ. Entowol. 58(3):414415 June 1965. feet above the cotton plants, at rates between about50 Thomas et al. J. Econ. Entowol. 59(1): 114-116 Febdroplets and about500 droplets per inch, the improve- Iuafy1966- ment which consists ofthe step of spraying the cotton 5 Cleveland et E6011 Entowol 973-976with a solution comprising 1-6 pounds of TDE [1,1- August1966' dichloro2,2-bis(parachlorophenyl) ethane] per gallon ggg zg Econ Entowol' 60(4):1121-1127 Of cyclohexanone- C Brazzel et al., JfEcon. Entowol. 61(2):408-413 April 2. The process of claim 1 wherein the solutlon com- 10 195prises 5-6 pounds of TDE per gallon of cyclohexanone.

3. The process of claim 2 wherein the solution is SHEP K-ROsEPrimaryExaminer sprayed at the rate of 0.26.0 pounds of toxicant per US. CL

acre in droplets in the size range of 50-100 microns. 15 424 213

